#include<stdio.h>
int main()
{
	int sum = 0;
	int arr[10] = {0};
	for (int i = 1; i <= 10; i++)
	{
		scanf_s("%d", &arr[i]);
		sum += arr[i];
	}
	double avg = 0;
		avg = sum / 10.0;
		printf("%lf\n", avg);
	return 0;
}